E36 ‘94 325i problems starting, runs fine

[BackyardBeamer]

Hey there, I own a 1994 325i automatic sedan, my car has a 183k miles and has always been serviced regularly and runs very strong, my problem is sometimes the car does not want to start. Reoccurring symptoms that started off bad and got worse.

Car went from starting fine to starting on the fifth-eighth crank.
Car started to not start on first cranking try, even after 10 cranks, (Sometimes engine would fire like 1/2? Stutter terribly and kill itself out)
Car would start if let fuel injectors prime 1-2 times after this
Car got worse and started needing a 3rd prime
Cold start use to be better, hot start worse, now it doesn’t matter.

Replaced fuel pump about a year ago (drove car fine for 40 miles, parked and wouldn’t start, ended up being the fuel pump)


2 weeks ago
Recently replaced spark plugs with NGK platinums (oil was in all plug ports due to failed valve cover seal,
Cleaned ignition coils (don’t know how to test but the car doesn’t seem to have any misfires)
Replaced valve cover gasket (cleaned a lot of built up grease off motor)
Replaced s belt and ac belt
Replaced air filter
Replaced crankshaft position sensor (bimmerforums turned me in that direction after I couldn’t figure anything else out)


Car will fire fine after 2-3 cranks randomly after crank sensor replaced (randomly)
Car will not fire after 5 trys of cranking 10 times+ (randomly)
Car will not fire and when it does fire need a minute to idle fine due to stuttering (almost like a slight misfire)
Car will fire fine and drive fine no problems (randomly)

Only once have I ever noticed a power difference while driving and that was right after a long waited rough start and it evened out.

That’s all the info I have for you guys , if anyone has any ideas why my car doesn’t like to start randomly I’d love to hear them.

Do I need to check fuel pressure and how?
Do I need to do a compression test?
How can I test potential bad ignition coil?
Could a vacuum leak do this? A vacuum would hinder performance no?

Thank you very much.

[Mless5]

Check the fuel pressure, clogged up filter could be the root cause of your issue. Also, read through here: https://www.bimmerforums.com/forum/s...ressure-on-m50

[shadowpuck]

agreed - assuming when it won't start its a crank, no start - i'd want to replace the fuel filter if it hasn't been already, and certainly if it wasn't replaced when the fuel pump was replaced.
and, yup, check fuel pressure....

[bmwdirtracer]

If this car came to my shop with this issue, I would (1) read codes, (2) look at live data for the intake air temp and coolant temp and MAF, (3) do a smoke test of the intake system, and then (4) do a fuel pressure test, particularly noting whether the pressure drops off completely within, say, 10 minutes after shut-down.

[shadowpuck]

If this car came to my shop with this issue, I would (1) read codes, (2) look at live data for the intake air temp and coolant temp and MAF, (3) do a smoke test of the intake system, and then (4) do a fuel pressure test, particularly noting whether the pressure drops off completely within, say, 10 minutes after shut-down.

listen to chris - he's done this once or twice!

[BackyardBeamer]

Great advice, so my filter is changed, no noticeable differences. I have primed the key twice and on the fifth second of the second prime i start the car and it has so far had a 90% success rate, don’t know if that helps or not.

So I bought an obdi scanner for bmw but I cannot get it to read any codes, also, no cel while driving, and I tried to get the car to give me Morse code on the cel and it only does one blink and a solid long blink, which I couldn’t find that as a code online??

And how do I read live data ? Diag machine?

So I can’t really do any of these tests expect maybe coolant temp? My coolant sensor is bad because even with a full radiator and reservoir my check panel reads “add engine coolant”.

Don’t know how to test intake temp and tbh been scared to touch the MaF so I haven’t even cleaned it.

My air filter did get pretty gross before I changed it.

[shadowpuck]

just fyi - we try to hold ourselves to a better standard here in this forum and keep the foul language out....

what scanner did you buy?

those are the tests that need to be done.

a decent bmw scan tool would perform these tests (minus fuel pressure) on your car. you can build your own scan tool using a laptop, INPA software, and the appropriate cable/20 pin connector.

the coolant sensor you are speaking of is the coolant level sensor.

i have, admittedly, never been a fan of MAF cleaning - usually if it needs to be cleaned it's obvious (like debris stuck on the filament, etc.).

also, just to add - a shop familiar with older BMWs should be able to perform these types of test readily....

are you running a stock air filter/setup?

as chris mentioned - i'd want to know any codes, see the data, and look at fuel pressure. smoke test is always a good idea.

[BackyardBeamer]

Sorry about the language I fixed it.

I called around and found a reputable shop that will do those tests in a diag for $104. Not many choices here so I think I’ll let him mess with it, if it’s expensive to fix I’ll try to get results and diy it.

[shadowpuck]

keep us updated - never a bad idea to have good shop diag the issue and then you can decide if you want to DIY or not.